A dual-motor coaxial two-speed electric drive axle

Abstract

The present invention discloses a two-speed electric drive axle with two motors coaxially arranged, which includes two drive motors A and B, a two-speed planetary reduction mechanism, and a planetary differential. The output shaft of drive motor A is connected to an input end of the planetary differential through a planetary gear set with a fixed speed ratio. The output shaft of drive motor B is connected to the input end of the two-speed planetary reduction mechanism, and the output end of the two-speed planetary reduction mechanism is connected to the other input end of the planetary differential. The planetary differential includes two output ends, and the two output ends are respectively connected to an output half shaft. The two output half shafts are arranged in opposite directions and their axes are on the same straight line. Moreover, the output shafts of both drive motors A and B are of hollow shaft structure, and the free ends of the two output half shafts pass through the hollow shafts of the drive motors respectively and are connected to the planetary differential. The two-speed electric drive axle with two motors coaxially arranged provided by the present invention can achieve stepless speed change, and has a compact structure and is convenient for installation and layout.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical and vehicle transmissions, and more specifically, relates to a two-speed electric drive axle with two motors coaxially arranged. Background Art

[0002] As a common transmission mechanism, the drive axle is widely used in the transmission fields of machinery and vehicles. To adapt to the development of new energy vehicle technologies, electric drive axles driven by drive motors have emerged. Most of the electric drive axles on the market are single-speed electric drive axles, with relatively high energy consumption and unable to meet relatively complex speed change requirements. Moreover, the structures of the two-speed electric drive axles on the market are complex, and the internal structures are not compact enough. Therefore, their volumes are often large and they are not easy to install and arrange. Therefore, how to provide a two-speed electric drive axle structure with a compact structure and convenient installation and arrangement is an urgent problem to be solved in this field. Summary of the Invention

[0003] Aiming at the defects of the prior art, the purpose of the present invention is to provide a two-speed electric drive axle with two motors coaxially arranged, which has a compact structure and is convenient for installation and arrangement.

[0004] To achieve the above purpose, the present invention provides a two-speed electric drive axle with two motors coaxially arranged, including two drive motors A and B, a drive axle housing, and a two-speed planetary reduction mechanism and a planetary differential arranged in the drive axle housing. Among them,

[0005] The output shaft of drive motor A is connected to an input end of the planetary differential through a planetary gear set with a fixed speed ratio. The output shaft of drive motor B is connected to the input end of the two-speed planetary reduction mechanism. The output end of the two-speed planetary reduction mechanism is connected to the other input end of the planetary differential. The planetary differential includes two output ends. One output end of the planetary differential is connected to the left output half shaft, and the other output end is connected to the right output half shaft. The two output half shafts are arranged in the opposite direction and their axes are on the same straight line;

[0006] The output shafts of the two drive motors A and B are both of hollow shaft structures. The free end of the right output half shaft passes through the hollow shaft of drive motor B and penetrates through the two-speed planetary reduction structure to be connected to the planetary differential. The free end of the left output half shaft passes through the hollow shaft of drive motor A and penetrates through the planetary gear set with a fixed speed ratio to be connected to the planetary differential.

[0007] The two-speed electric drive axle with two motors coaxially arranged provided by the present invention, by setting a two-speed planetary reduction mechanism that can achieve two-speed reduction gears, can cooperate with the output speed range of the drive motor to achieve stepless speed change. At the same time, by using the space of the drive motor to connect the free end of the output half shaft to the planetary differential through the center of the motor, the overall axial layout space of the electric drive axle can be effectively saved, making the overall layout of the electric drive axle more convenient.

[0008] In one embodiment, the two-speed planetary reduction mechanism includes a reduction planetary gear set, a switching device, and a double-star planetary gear set. The reduction planetary gear set includes a reduction planetary sun gear, reduction planetary planet gears, a reduction planetary ring gear, and a reduction planetary carrier. The double-star planetary gear set includes a double-star planetary sun gear, two double-star planetary planet gears A and B, a double-star planetary carrier, and a double-star planetary ring gear. Among them,

[0009] The reduction planetary sun gear is connected to the output end of the drive motor B, the reduction planetary ring gear is fixedly connected to the drive axle housing, the reduction planetary planet gears are connected to the double-star planetary sun gear through the reduction planetary carrier, the double-star planetary sun gear meshes with the double-star planetary planet gear A and the double-star planetary planet gear B in sequence, and the double-star planetary ring gear is fixedly connected to the housing of the planetary differential;

[0010] When the switching device is manipulated to connect the double-star planetary carrier to the double-star planetary sun gear, the double-star planetary gear set is in an overall rotation working state, making the two-speed planetary reduction mechanism in the high gear; when the switching device is manipulated to connect the double-star planetary carrier to the drive axle housing, the double-star planetary gear set is in a reduction working state, making the two-speed planetary reduction mechanism in the low gear.

[0011] In one embodiment, the switching device adopts a clutch and a brake. When the clutch is engaged and the brake is disengaged, the double-star planetary carrier is connected to the double-star planetary sun gear through the clutch. When the clutch is disengaged and the brake is engaged, the double-star planetary carrier is connected to the drive axle housing through the brake.

[0012] In one embodiment, the switching device adopts a synchronizer sleeve, and the double-star planetary carrier selectively connects the double-star planetary sun gear or the drive axle housing through the synchronizer sleeve.

[0013] In one embodiment, the planetary differential includes a compound planetary differential and a differential lock. The compound planetary differential includes a differential housing and two sun gears and two planet gears arranged in the differential housing. The two sun gears are correspondingly connected to the two output half shafts, the two planet gears are correspondingly meshed with two of the sun gears, and the two planet gears share a differential housing and are externally meshed with each other to form the meshing teeth of the compound planetary differential, constituting the torque loop of the two output half shafts; the differential lock is used to lock the compound planetary differential.

[0014] In one embodiment, the differential lock adopts an end face differential lock or a wet clutch differential lock.

[0015] In one embodiment, free ends of the two output half shafts are both drivingly connected to a wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a two-speed electric drive axle with two motors coaxially arranged according to an embodiment of the present invention. Specific embodiments

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] To solve the problems of complex structure, lack of compactness and difficult installation existing in traditional two-speed electric drive axles, the present invention provides a two-speed electric drive axle with two motors coaxially arranged, which can be applied to the fields of machinery and vehicle transmission. The present invention mainly describes this two-speed electric drive axle with its application in the field of vehicle transmission as an example.

[0019] The two-speed electric drive axle with two motors coaxially arranged provided in this embodiment includes two drive motors A and B, a drive axle housing, and a two-speed planetary reduction mechanism and a planetary differential arranged inside the drive axle housing.

[0020] Among them, the output shaft of drive motor A is connected to an input end of the planetary differential through a planetary gear set with a fixed speed ratio. The output shaft of drive motor B is connected to the input end of the two-speed planetary reduction mechanism. The output end of the two-speed planetary reduction mechanism is connected to the other input end of the planetary differential. The planetary differential includes two output ends. One output end of the planetary differential is connected to the left output half shaft, and the other output end is connected to the right output half shaft. The two output half shafts are arranged in opposite directions and their axes are on the same straight line. The free ends of the two output half shafts are both drivingly connected to a wheel.

[0021] In this embodiment, drive motors A and B are used to output power. The two-speed planetary reduction mechanism is used to adjust the output of drive motor B to a suitable rotational speed. The two-speed planetary reduction mechanism provided in this embodiment can achieve rotational speed outputs of two reduction gears, namely high gear and low gear. The planetary gear set with a fixed speed ratio is used to ensure no power interruption during the gear shifting process of the two-speed planetary reduction mechanism and realize continuous power output. The planetary differential is used to distribute the torque to the left output half shaft and the right output half shaft to coordinate the driving of the vehicle forward.

[0022] The working principle of the two-speed electric drive axle with two motors coaxially arranged applied to the vehicle field provided in this embodiment is as follows: When the vehicle is driving normally, only drive motor A can be used to drive the vehicle to realize continuous power output of the electric drive axle, improving the shifting comfort and reliability of the vehicle. When the vehicle needs greater power, drive motor B can be started as an auxiliary power source. According to the running speed of the vehicle, the high gear and the low gear can be switched in a timely manner to meet the power requirements of the vehicle, and at the same time, the economy of the system is improved.

[0023] In addition, the output shafts of the two drive motors A and B provided in this embodiment are both configured as hollow shaft structures. The free end of the right output half shaft passes through the hollow shaft of the drive motor B and penetrates through the two-speed planetary reduction structure to be connected to the planetary differential, and the free end of the left output half shaft passes through the hollow shaft of the drive motor A and penetrates through the planetary gear train with a fixed speed ratio to be connected to the planetary differential. This embodiment utilizes the space of the drive motor to connect the free end of the output half shaft to the planetary differential through the center of the motor, which can effectively save the overall axial layout space of the electric drive axle and make the overall layout of the electric drive axle more convenient.

[0024] The two-motor coaxial two-speed electric drive axle provided in this embodiment, by setting a two-speed planetary reduction mechanism that can achieve two-speed reduction gears, can cooperate with the output speed range of the drive motor to achieve stepless speed change. At the same time, by utilizing the space of the drive motor to connect the free end of the output half shaft to the planetary differential through the center of the motor, it can effectively save the overall axial layout space of the electric drive axle and make the overall layout of the electric drive axle more convenient.

[0025] In one embodiment, as Figure 1 shown, the two-speed planetary reduction mechanism provided in the above embodiment includes a reduction planetary gear train, a switching device, and a double-star planetary gear train. The reduction planetary gear train includes a reduction planetary gear train sun gear 202, a reduction planetary gear train planetary gear 203, a reduction planetary gear train ring gear 205, and a reduction planetary gear train frame 204. The double-star planetary gear train includes a double-star planetary gear train sun gear 208, a double-star planetary gear train planetary gear A 209, a double-star planetary gear train planetary gear B 210, a double-star planetary gear train frame 211, and a double-star planetary gear train ring gear 212.

[0026] The connection relationships of the components in the two-speed planetary reduction mechanism provided in this embodiment are as follows: The reduction planetary gear train sun gear 202 is connected to the output end of the drive motor B. The reduction planetary gear train ring gear 205 is connected to the drive axle housing. The reduction planetary gear train planetary gear 203 is connected to the double-star planetary gear train sun gear 208 through the reduction planetary gear train frame 204. The double-star planetary gear train sun gear 208 meshes with the double-star planetary gear train planetary gear A 209 and the double-star planetary gear train planetary gear B 210 in sequence. The double-star planetary gear train ring gear 212 is fixedly connected to the housing of the planetary differential.

[0027] When the switching device is manipulated to connect the double-star planetary gear train frame 211 to the double-star planetary gear train sun gear 202, the double-star planetary gear train is in an overall rotating working state, making the two-speed planetary reduction mechanism in the high gear. When the switching device is manipulated to connect the double-star planetary gear train frame 211 to the drive axle housing, the double-star planetary gear train is in a decelerating working state, making the two-speed planetary reduction mechanism in the low gear.

[0028] Specifically, when the switching device can use the clutch 206 and the brake 207, the clutch 206 and the brake 208 are respectively combined to form two working gears of the two-speed planetary reduction mechanism, that is, when the clutch 206 is closed and the brake 207 is separated, the double-star planetary gear frame 211 is connected to the double-star planetary gear sun gear 208 through the clutch 206, and the two-speed planetary reduction mechanism is in the high-speed reduction gear; when the clutch 206 is separated and the brake 207 is engaged, the double-star planetary gear frame 211 is connected to the drive axle housing through the brake 207, and the two-speed planetary reduction mechanism is in the low-speed reduction gear; when the clutch 206 and the brake 207 are separated, the two-speed planetary reduction mechanism is in neutral. Of course, the clutch 206 and the brake 207 provided in this embodiment can also be replaced with a synchronous gear sleeve to achieve high-low gear switching.

[0029] This embodiment simplifies the original bevel gear structure of the traditional electric drive axle and converts it into a reduction planetary gear and a double-star planetary gear combination, which can further reduce the space requirement for the entire vehicle layout and realize independent distributed drive of the front and rear axles of the vehicle.

[0030] In one embodiment, the planetary gear differential adopts a compound planetary gear differential, which includes a differential housing and two sun gears 213, 216 and two planetary gears 214, 215 arranged in the differential housing. The two sun gears are correspondingly connected to two output half shafts, and the two planetary gears are correspondingly meshed with two of the sun gears. The two planetary gears share a differential housing and are externally meshed with each other to form meshing teeth of the compound planetary gear differential, forming a torque circuit of the two output half shafts to realize the function of the differential.

[0031] Furthermore, the planetary gear differential provided in this embodiment can also be equipped with a differential lock 217 for locking the compound planetary gear differential to meet the need for the vehicle to escape from a difficult road. Specifically, the differential lock 217 provided in this embodiment can be an end differential lock or a wet clutch differential lock.

[0032] In this embodiment, the output shaft of the driving motor A drives the reduction planetary gear sun gear 221 in the fixed speed ratio planetary gear. The reduction planetary gear ring 224 in the fixed speed ratio planetary gear and the drive axle housing are fixedly connected. The power is transmitted to the reduction planetary gear frame 223 therein through the reduction planetary gear 222 in the fixed speed ratio planetary gear. The reduction planetary gear frame 223 is directly connected to the housing of the planetary gear differential to form a continuously controllable power transmission route.

[0033] After the driving motor B converts electrical energy into mechanical energy, it enters the planetary differential through the two-stage planetary reduction mechanism. The planetary differential is realized by a compound planetary gear set without a ring gear. Through tooth ratio changes, the planetary differential can achieve a 1:1 torque output between the left and right wheels in a compact space, meeting the requirement that the torque outputs of the left and right wheels are consistent when the vehicle passes through different road surfaces. The driving motor A is connected to the housing of the planetary gear set with a fixed reduction ratio and the planetary differential to meet the requirement of continuous power output. The planetary differential can be locked by the differential lock 217 to meet the requirement of the vehicle getting out of trouble on difficult road surfaces. The power can also be reversely transmitted in the two-stage electric drive axle system, and the energy utilization rate of the vehicle can be improved by recovering energy through the driving motors A and B.

[0034] Compared with the traditional two-stage electric drive axle, the dual-motor coaxial two-stage electric drive axle provided in this embodiment has the following effects: (1) By setting up a two-stage planetary reduction mechanism to achieve two reduction gears, it can cooperate with the output speed range of the driving motor to achieve stepless speed change; (2) Using the space of the driving motor to connect the free end of the output half shaft to the planetary differential through the center of the motor can effectively save the overall axial layout space of the electric drive axle and make the overall layout of the electric drive axle more convenient; (3) Using a double-star planetary gear set can reduce the intermediate ratio of the two-stage speed ratio, making the utilization effect of the high-efficiency area of the motor better, effectively reducing the energy loss of the electric drive axle, and improving the economy of the electric drive axle; (4) Adopting two driving motors can achieve a smooth transition of torque during power switching.

[0035] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A two-speed electric drive axle with two motors coaxially arranged, characterized in that, It includes two drive motors A and B, a drive axle housing, and a two-speed planetary reduction mechanism and a planetary differential arranged within the drive axle housing. Among them, the output shaft of drive motor A is connected to an input end of the planetary differential through a planetary gear set with a fixed speed ratio, the output shaft of drive motor B is connected to the input end of the two-speed planetary reduction mechanism, the output end of the two-speed planetary reduction mechanism is connected to the other input end of the planetary differential, the planetary differential includes two output ends, one output end of the planetary differential is connected to the left output half shaft, and the other output end is connected to the right output half shaft. The two output half shafts are arranged in opposite directions and their axes are on the same straight line; the output shafts of both drive motors A and B are of hollow shaft structure. The free end of the right output half shaft passes through the hollow shaft of drive motor B and penetrates through the two-speed planetary reduction structure to be connected to the planetary differential, and the free end of the left output half shaft passes through the hollow shaft of drive motor A and penetrates through the planetary gear set with a fixed speed ratio to be connected to the planetary differential; the two-speed planetary reduction mechanism includes a reduction planetary gear set, a switching device, and a double-star planetary gear set. The reduction planetary gear set includes a reduction planetary sun gear, reduction planetary planet gears, a reduction planetary ring gear, and a reduction planetary carrier. The double-star planetary gear set includes a double-star planetary sun gear, two double-star planetary planet gears A and B, a double-star planetary carrier, and a double-star planetary ring gear. Among them, the reduction planetary sun gear is connected to the output end of drive motor B, the reduction planetary ring gear is fixedly connected to the drive axle housing, the reduction planetary planet gears are connected to the double-star planetary sun gear through the reduction planetary carrier, the double-star planetary sun gear meshes with the double-star planetary planet gear A and the double-star planetary planet gear B in sequence, and the double-star planetary ring gear is fixedly connected to the housing of the planetary differential; when the switching device is manipulated to connect the double-star planetary carrier to the double-star planetary sun gear, the double-star planetary gear set is in an overall rotation working state, making the two-speed planetary reduction mechanism in the high gear; when the switching device is manipulated to connect the double-star planetary carrier to the drive axle housing, the double-star planetary gear set is in a decelerating working state, making the two-speed planetary reduction mechanism in the low gear.

2. The two-speed electric drive axle with two motors coaxially arranged according to claim 1, characterized in that, The switching device uses a clutch and a brake. When the clutch is engaged and the brake is disengaged, the double-star planetary carrier is connected to the double-star planetary sun gear through the clutch. When the clutch is disengaged and the brake is engaged, the double-star planetary carrier is connected to the drive axle housing through the brake.

3. The two-speed electric drive axle with two motors coaxially arranged according to claim 1, characterized in that, The switching device uses a synchronizer sleeve, and the double-star planetary carrier selectively connects to the double-star planetary sun gear or the drive axle housing through the synchronizer sleeve.

4. The two-speed electric drive axle with two motors coaxially arranged according to claim 1, characterized in that, The planetary differential includes a compound planetary differential and a differential lock. The compound planetary differential includes a differential case and two sun gears and two planet gears disposed within the differential case. The two sun gears are correspondingly connected to two output half shafts. The two planet gears are correspondingly meshed with two of the sun gears, and the two planet gears share a differential case and are externally meshed with each other to form the meshing teeth of the compound planetary differential, thereby forming a torque circuit for the two output half shafts. The differential lock is used to lock the compound planetary differential.

5. The two-speed electric drive axle with two motors coaxially arranged according to claim 4, characterized in that, The differential lock adopts an end face differential lock or a wet clutch differential lock.

6. The two-speed electric drive axle with two motors coaxially arranged according to claim 1, characterized in that, Free ends of the two output half shafts are both drivingly connected to a wheel.

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